Method and system for managing a storage network to reduce power consumption

ABSTRACT

Methods, computer systems, and computer program products are provided for managing a storage network system is provided. The storage network system includes a plurality of zones. Each of the plurality of zones includes at least one storage network device. A link-down event associated with one of the storage network devices is detected. One of the plurality of zones is identified is identified as being unused if the zone is not accessed by another of the storage network devices in another of the plurality of zones and if the zone does not access another of the storage network devices in another of the plurality of zones.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to storage networks, and moreparticularly to methods, computer systems, and computer program productsfor managing storage networks to reduce power consumption.

2. Description of the Related Art

Modern storage networks (or Storage Area Networks (SAN)), typicallyinclude multiple “initiator” devices (e.g., hosts) and “target” devices(e.g., storage devices) interconnected through a storage interface, suchas a Serial Attached SCSI (SAS) storage interface.

A SAS network (or SAS domain) also includes one or more SAS expanderdevice which function as a switch and performs routing of a SAS framefrom an initiator to a target. The SAS expander performs a SAS discoveryprocess at initialization to obtain various information, such as the SASaddresses, device types (initiator, target, and expander), and supportedprotocols of all devices in the SAS domain and the identity of the SASexpanders to which all devices in the SAS domain are physicallyconnected and position information indicating to which physicalconnection (PHY) of the SAS expanders the devices are connected. The SASexpander also generates a routing table on the basis of the aboveinformation and uses it for the routing of the SAS frame.

Moreover, the SAS supports a zoning function for controlling an accessbetween devices. This function is used to assign zone identifications toSAS devices and to set which zones are allowed to access each other.Normally, one or more hosts are defined for a zone, one or more storagesare defined for another zone, and the accessibility of the zones isdefined for operation. Zoning is a function essential to many users forsecurity.

A significant issue in storage networks, including SAS networks, is thatof the power consumption of the various devices within the networks. Oneof the reasons managing the power consumption is difficult is thatconventional networks do not include the functionality to determinewhich devices within the network are accessing other devices or beingaccessed from other devices.

SUMMARY OF THE DESCRIBED EMBODIMENTS

In one embodiment, a method for managing a storage network system isprovided. The storage network system includes a plurality of zones. Eachof the plurality of zones includes at least one storage network device.A link-down event associated with one of the storage network devices isdetected. One of the plurality of zones is identified as being unused ifthe zone is not accessed by another of the storage network devices inanother of the plurality of zones and if the zone does not accessanother of the storage network devices in another of the plurality ofzones.

In another embodiment, a routing storage network device for managing astorage network system is provided. The storage network includes aplurality of zones. Each of the plurality of zones includes at least onestorage network device. The routing storage network device includes acomputer-readable medium and a processor in operable communication withthe computer-readable medium. The processor is adapted to detect alink-down event associated with one of the storage network devices andidentify the respective zone of the one of the storage network devicesas being unused if the zone is not accessed by another of the storagenetwork devices in another of the plurality of zones and if the zonedoes not access another of the storage network devices in another of theplurality of zones.

In a further embodiment, a computer program product for managing astorage network system is provided. The storage network system includesa plurality of zones. Each of the plurality of zones includes at leastone storage network device. The computer program product hascomputer-readable program code portions stored thereon. Thecomputer-readable program code portions include a first executableportion and a second executable portion. The first executable portion isfor detecting a link-down event associated with one of the storagenetwork devices. The second executable portion is for identifying therespective zone of the one of the storage network devices as beingunused if the zone is not accessed by another of the storage networkdevices in another of the plurality of zones and if the zone does notaccess another of the storage network devices in another of theplurality of zones.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict embodiments of the invention and are not therefore to beconsidered to be limiting of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings, in which:

FIG. 1 is block diagram of a storage network according to one embodimentof the present invention;

FIG. 2 is a block diagram of the storage network of FIG. 1 illustratinga zoning scheme within the storage network;

FIG. 3 is a block diagram of the storage network of FIG. 2 illustratingaccessibility between the zones, according to one embodiment of thepresent invention;

FIG. 4 is a flow chart of a method for managing a storage networkaccording to one embodiment of the present invention; and

FIG. 5 is a block diagram of an exemplary storage network according toanother embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

According to one aspect of the present invention, a method is providedfor reducing power consumption in an SAS domain by using zone settinginformation. In one embodiment, a routing storage network device (e.g.,an SAS expander) identifies an end device which is not accessed byanyone or which does not access anyone at that time on the basis of thezone setting information and the routing table. The SAS expander closelycontrols the power state of the end devices and the connected physical(PHY) state, thereby achieving power consumption saving.

The SAS expander is thus provided with functionality for identifying adevice which is not accessed by anyone or which does not access anyoneat that time on the basis of the zone setting information and therouting table during link-down of an arbitrary device or at the time ofchange in zone setting, as well as for identifying a device which hasthe possibility of being accessed and is deliberately placed in adisabled state by the SAS expander on the basis of the zone settinginformation and the routing table during link-up of an arbitrary deviceor at the time of change in zone setting.

The SAS expander is also configured to minimize the power consumption ofthe identified target device by spin-down or the like by using anexisting technology and disabling the PHY connected to the identifieddevice by using an existing technology.

As a result, embodiments of the present invention enable powerconsumption reduction saving without use of any particular device(hardware), without departing from the SAS standard, without losing dataavailability, and with no or minimum effect on performance.

The present invention is a technique in which the SAS expanderidentifies a device which is not accessed by anyone or which does notaccess anyone surely at that time by utilizing the zone settinginformation and reduces the power consumption of the device as much aspossible, thereby achieving energy saving. However, it should beunderstood that the method(s) described herein may be applicable toother storage networks (or Storage Area Network (SAN)) interfacesbesides SAS, such as a Fibre Channel-based storage networks andiSCSI-based storage networks using a switch.

FIG. 1 illustrates an SAS domain 100 according to one embodiment of thepresent invention. The SAS domain 100 includes a first host 102, asecond host 104, a first SAS expander 106, a second SAS expander 108,and six SAS disks 110-120. The first and second hosts 102 and 104 are inoperable communication with the SAS disks 110-120 through the SASexpanders 106 and 108 as shown in FIG. 1.

As shown, in FIG. 2, the SAS domain may be assumed to includes aplurality of zones defined as follows: Zone 11-Host 1; Zone 12-Host 2;Zone 21-SAS disk 1; Zone 22-SAS disk 2 and SAS disk 3; Zone 31-SAS disk4; and Zone 32-SAS disk 5 and SAS disk 6.

Referring now to FIG. 3, accessibility to or from the respective zonesare assumed to be defined as follows: Zone 11<->Zone 21, Zone 22, Zone32; and Zone 12 <->Zone 31, Zone 22, Zone 32. Refer to FIG. 3 forclarification.

A zone manager (not shown) sets the zone setting information provided byusers to each of the SAS expanders 106 and 108. As an interface, a SASin-band Serial Management Protocol (SMP), the Ethernet, or the like isused. If the zoning function is enabled, the SAS expander implementszoning by reflecting the zone setting information on routing whenperforming SAS frame routing.

In one embodiment, a zone status table is added to the SAS expander(i.e., the first SAS expander 106 and/or the second SAS expander 108).This table is used in “unused zone shutdown processing” described hereinand simply needs to hold a 1-bit alive/down state for each zone.

FIG. 4 illustrates a method 150 for managing a storage network system,according to one embodiment of the present invention. It should beunderstood that the steps shown in FIG. 4 present a simplified versionof the method 150, which may include addition steps, as described ingreater detail below. At step 152, the method 150 begins with thestorage network (e.g., a SAS network) being initiated. The storagenetwork includes multiple zones, with each zone including one or morenetwork devices. At step 154, a link-down event (e.g., a device failure)associated with a storage network device within the network is detected.At step 156, a zone in the storage network is identified as being“unused.” However, this identification only occurs if the zone is notaccessed by storage network devices in other zones and the zone does notaccess storage network devices in other zones. At step 158, the method150 ends, with for example, the power consumption of the link-downdevice being reduced.

As mentioned above, additional details of the method 150 will now bedescribed. The SAS expander (106 and/or 108) and the SAS device (i.e.,the first host 102, the second host 104, and/or one of more of the SASdisks 110-120) conventionally perform initialization at the time ofpower-on. Specifically, the SAS discovery process is performed to obtainthe SAS addresses, the device types, supported protocols, connected SASexpanders, and PHY positions of all devices in the SAS domain. It shouldbe understood that the SAS expanders 106 and 108 may be self-configuringexpanders, as is commonly understood.

It is assumed that one SAS device breaks down and the connected SASexpander detects a link-down (i.e., a device failure, a cable failure, aplanned device power interruption, or the like). The SAS expander, upondetecting the link-down, immediately transmits a BROADCAST signal to alldevices in the SAS domain 1 to give notice of the link-down condition.Thereafter, the SAS expander performs the SAS discovery process againand updates the routing table stored therein. In one example, the firsthost 102 breaks down and the first SAS expander 106 detects thelink-down of the first host 102.

The SAS expander then performs the following unused-zone shutdownprocessing. First, the SAS expander identifies the zone to which thelink-down device belongs on the basis of the zone table. In the example,in which the first host 102 breaks down, the identified zone is Zone 11(FIG. 3). The SAS expander then checks whether all devices in theidentified zone are in the link-down state. In this operation, the SASexpander refers to the zone table and the routing table. If all devicesare in the link-down state, the SAS expander places the zone (e.g., Zone11) in a down state on the zone status table. Otherwise, the SASexpander terminates the unused-zone shutdown processing at this point.If the zoning function itself is disabled, the SAS expander terminatesthe unused-zone shutdown processing directly. In the example in whichthe first host 102 breaks down, Zone 11 is disabled.

Subsequently, the SAS expander checks whether there is a zone satisfyingthe following condition as a result of placing the zone (e.g., Zone 11)in the down state. The condition is whether there are any zones notbeing accessed from any effective zone and not accessing any effectivezone. Such a zone is determined to be an “unused” zone. In the exampleinvolving the first host 102, Zone 21 is an unused zone. Zone 22 andZone 32 do not satisfy the conditions as they are accessible from Zone12.

The SAS expander then initiates shutdown processing. The SAS expanderchecks the device type of the device(s) included in the unused zone(s).Note that device types have already been obtained at initialization.

If the device types of all devices are “target” devices, the SASexpander determines the devices in the unused zone to be storagedevices. In the example involving the first host 102, Zone 21 includesonly the SAS disk 1 and is therefore applicable.

The SAS expander then determines whether the storage devices aredirectly connected to the expander (e.g., the first SAS expander 106) onthe basis of the routing table. If there is a directly-connected device,the SAS expander performs processing of minimizing the power consumptionof the storage device, such as transmitting an SCSI command to spin downthe disk. If the target device is equipped with an external controlwhich shifts to a lower electric power state such as power-off, such afunction may also be used. Moreover, the SAS expander disables the PHYconnection (or a plurality of PHY connections in the case of amulti-lane) connected to the storage to prevent the IDLE primitive fromflowing. If the SAS expander supports the low power mode for each PHY,the use of the low mode enhances the effect. The storage spin-down andthe disabling of the PHY are utilized to achieve a power-saving effect.In the first host 102 example, the first SAS expander 106 spins down SASdisk 110 and disables the connected PHY.

If the device type of all devices is “initiator,” or includes both ofthe “initiator” type and the “target” type, the SAS expander determineswhether these devices are directly connected to the SAS expander on thebasis of the routing table. If there is a device directly connected tothe SAS expander, the SAS expander disables the PHY connection (or aplurality of PHY connections in the case of a multi-lane) connected tothe device to prevent the IDLE primitive from flowing. If the expandersupports the low power mode for each PHY, the use of the mode enhancesthe effect. A power saving effect is achieved by disabling the PHY.

The shutdown processing described herein is performed only for a zoneidentified as an unused zone. Therefore, the processing is not performedfor a PHY linked down first due to a failure or the like, for example.This enables the SAS expander to detect link-up if the broken devicerecovers.

If the SAS expander detects a new device due to the recovery of a brokendevice, the SAS expander performs a process in reverse to that describedabove (“recovery” processing). For example, the first host 102 recoversand the link-up occurs.

In such a situation, the SAS expander checks a zone to which therecovered device belongs on the basis of the zone table (e.g., Zone 11for the first host 102). The SAS expander then checks for zonesaccessible from the zone of the recovered device using the zonepermission table (e.g., Zones 21, 22, and 32 are accessible from Zone11). Next, the SAS expander checks the zone status table to confirmwhether the zone checked in the above step is placed in the down stateas part of the unused-zone shutdown processing. (e.g., Zone 21).

If the zone is in the down state, the SAS expander performs power-onprocessing of the devices in that zone to place the zone in the alivestate on the zone status table. The power-on processing is to enable theconnected PHY for a device directly connected to the SAS expander amongthe devices in the zone. In the case of a “target” device type, the SASexpander further performs spin-up or other recovery processing from thedisabled state caused by the shutdown processing described above. In theexample in which the first host 102 has recovered, the first SASexpander 106 enables the connected PHY and further spins up SAS disk110.

For a device which is once identified as an unused zone by the SASexpander and for which shutdown processing is performed, the connectedPHY is disabled. Therefore, even if some event occurs for the device inthe zone during the disabled state, the SAS expander is not aware of theevent. However, when the device using the unused zone appears in the SASdomain, the SAS expander performs power-up processing of the unusedzone. Thereafter, an event of the device is correctly broadcasted. Thepresent invention is based on an idea that other devices in the SASdomain do not need to grasp the latest state of the device which is notaccessed by anyone or which does not access anyone.

As described above, the present invention is a technique in which theSAS expander saves power by identifying a device which is not accessedby devices and which does not access other devices by using the zonesetting information and reducing the power consumption of the device,and the storage network as a whole, as much as possible.

In the case where a host device breaks down, the SAS expander determinesa storage device used only by the host to be unnecessary and disablesthe storage device. In the case where a storage device breaks down and apath to the host is unnecessary, the SAS expander disables the path tothe host device. It should also be understood that steps 3 and 4 may beperformed when a change in zone setting is applied to the SAS expander.

Additionally, the SAS expander may perform the method(s) describedherein on a regular, scheduled basis. Such activity may have severalbenefits. If the host device is not connected yet, a storage device usedonly by the host device is disabled. If there is a backup storage orhost device, zoning is set in such a way that no one can access thebackup storage or host device in a normal standby state. As such, anyparticular setting is not needed and the SAS expander in the SAS domainautomatically maintains these devices in the minimum power consumptionstate. When backup operation or recovery is actually performed by usingthe backup storage or backup host, it is only necessary to change thezone setting dynamically.

Furthermore, method(s) described herein may be beneficial when a singlezone includes both of the host and the target in question. In theexample(s) described above, if all devices included in a particular zoneare in the link-down state, the SAS expander shuts down all devices inanother zone having been accessed only from or accessed only that zone.

However, if initiator and target elements are added, the followingpolicies may also be used. If all initiators included in a particularzone are in the link-down state, the SAS expander shuts down all targetsin another zone having been accessed only from the certain zone. If alltargets included in a particular zone are in the link-down state, theSAS expander shuts down all initiators in another zone having accessedonly the certain zone.

Such policies may be implemented in a manner similar to those describedabove. However, entries in the zone status table may be increased from 1bit to 2 bits to manage all initiator statuses in the zone and alltarget statuses in the zone, as opposed to managing one status of theentire zone. Then, when shutdown and recovery processing are performed,an unused zone is not identified, but an unused zone initiator group orunused zone target group is identified to perform shutdown processing orrecovery processing.

FIG. 5 shows one embodiment of a SAN 200 according to an embodiment ofthe present invention. In FIG. 5, servers 202 are coupled to datastorage devices 230 via SAN interconnect 204. Each server 202 and eachstorage device 230 is coupled to SAN interconnect 204. Servers 202 havedirect access to any of the storage devices 230 connected to the SANinterconnect 204. SAN interconnect 204 can be a high speed interconnect,such as Fibre Channel or small computer systems interface (SCSI). Inaddition, SAN interconnect 204 can be an Internet Small Computers SystemInterface (iSCSI), a Fiber Connectivity (FICON) storage protocol, orSerial Attached SCSI (SAS) attached storage. As FIG. 2 shows, theservers 202 and storage devices 230 comprise a network in and ofthemselves.

In the SAN 200 of FIG. 2, no server 202 is dedicated to a particularstorage device 230 as in a LAN. Any server 202 may access any storagedevice 230 on the SAN 200 in FIG. 2. Typical characteristics of a SAN200 may include high bandwidth, a multitude of nodes per loop, a largeconnection distance, and a very large storage capacity. Consequently,the performance, flexibility, and scalability of a Fibre Channel basedSAN 200 may be significantly greater than that of a typical SCSI basedsystem.

FIG. 5 also shows a network administrator 270 coupled to the SANinterconnect 204. Being able to effectively allocate storage 230 in aSAN 200 in a manner that provides for adequate data protection andrecoverability is of particular importance. Because multiple hosts mayhave access to a particular storage array 230 in a SAN 200, preventionof unauthorized and/or untimely data access is desirable. Zoning is anexample of one technique that is used to accomplish this goal. Zoningallows resources to be partitioned and managed in a controlled manner.The administrator 270 may be used to map hosts to storage and providecontrol to allocation of the storage devices 230.

Although the present invention has been described above on the basis ofthe embodiment, the technical scope of the present invention is notlimited to the above embodiment. It is apparent to those skilled in theart that various modifications or improvements can be added to the aboveembodiment.

It should be noted that execution orders of processes, such asoperations, procedures, steps and stages in the devices, systems,programs and methods shown in the scope of claims, the description andthe drawings, are not clearly specified particularly by use ofexpressions such as “before” and “prior to.” Therefore, those processesare executable in any orders unless an output from a preceding processis used in a process subsequent thereto. Even if any operational flow inthe scope of claims, in the description or in the drawings has beendescribed by use of expressions such as “firstly,” and “subsequently,”for the sake of convenience, this does not necessarily mean that theoperational flow has to be executed by an order indicated by theseexpressions.

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wired, optical fiber cable, RF, etc., or any suitable combination of theforegoing. Computer program code for carrying out operations for aspectsof the present invention may be written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Java, Smalltalk, C++ or the like and conventionalprocedural programming languages, such as the “C” programming languageor similar programming languages. The program code may execute entirelyon the user's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described above with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer, other programmable data processing apparatus, orother devices to cause a series of operational steps to be performed onthe computer, other programmable apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagram in the above figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions (i.e.,executable portions) for implementing the specified logical function(s).It should also be noted that, in some alternative implementations, thefunctions noted in the block may occur out of the order noted in thefigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. It will also be noted that each block of the block diagramsand/or flowchart illustration, and combinations of blocks in the blockdiagrams and/or flowchart illustration, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts, or combinations of special purpose hardware and computerinstructions.

While one or more embodiments of the present invention have beenillustrated in detail, one of ordinary skill in the art will appreciatethat modifications and adaptations to those embodiments may be madewithout departing from the scope of the present invention as set forthin the following claims.

What is claimed is:
 1. A method for managing a storage network systemcomprising a plurality of zones,each of the plurality of zonescomprising at least one storage network device, the method comprising:detecting a link-down event associated with one of the storage networkdevices; wherein The link-down event is at least one of a devicefailure, a cable failure, and a planned device power interruption;identifying one of a plurality of zones where the link-down evenoccurred; transmitting a broadcast signal in the storage network givingnotice of the detected link-down event, determining whether alternativestorage network devices in the identified one of the plurality of zoneswhere the link-down event occurred are in a link-down state, wherein atleast a zone table and a routing table is used for the determining; inresponse to all of the storage network devices being in the link downstate, placing the identified one of the plurality of zones where thelink-down event occurred in a down state; and identifying one of theplurality of zones as being unused if the zone is not accessed byanother of the storage network devices in another of the plurality ofzones and if the zone does not access another of the storage networkdevices in another of the plurality of zones.
 2. The method of claim 1,further comprising reducing power consumption of the zone identified asbeing unused.
 3. The method of claim 2, wherein each of the storagenetwork devices is a target storage network device, an initiator storagenetwork device, or a combination thereof.
 4. The method of claim 3,wherein the storage network system further comprises a routing storagenetwork device configured to communicatively interconnect the storagenetwork devices.
 5. The method of claim 4, wherein the storage networksystem is a Serial Attached SCSI (SAS) storage network system.
 6. Themethod of claim 4, wherein the reducing the power consumption of thezone identified as being unused comprises disabling a physicalconnection between the routing storage network device and the one of thestorage network devices.
 7. The method of claim 4, further comprisingidentifying the respective zone as being used if the zone is accessed byanother of the storage network devices in another of the plurality ofzones or if the zone does not access another of the storage networkdevices in another of the plurality of zones after the respective zoneis identified as being unused.
 8. A routing storage network device formanaging a storage network system comprising a plurality of zones, eachof the plurality of zones comprising at least one storage networkdevice, the routing storage network device comprising: acomputer-readable medium; and a processor in operable communication withthe computer-readable medium, the processor: detects a link-down eventassociated with one of the storage network devices, wherein thelink-down event is at least one of a device failure, a cable failure,and a planned device power interruption, identifies one of a pluralityof zones where the link-down event occurred, transmits a broadcastsignal in the storage network giving notice of the detected link-downevent, determines whether alternative storage network devices in theidentified one of the plurality of zones where the link-down eventoccurred are in a link-down state, wherein at least a zone table and arouting table is used for the determining; in response to all of thestorage network devices being in the link-down state, places theidentified one of the plurality of zones where the link-down eventoccurred in a down state; and identifies one of the plurality of zonesas being unused if the zone is not accessed by another of the storagenetwork devices in another of the plurality of zones and if the zonedoes not access another of the storage network devices in another of theplurality of zones.
 9. The routing storage network device of claim 8,wherein the processor reduces power consumption of the zone identifiedas being unused.
 10. The routing storage network device of claim 9,wherein each of the storage network devices is a target storage networkdevice, an initiator storage network device, or a combination thereof.11. The routing storage network device of claim 10, wherein the routingstorage network device is configured to communicatively interconnect thestorage network devices.
 12. The routing storage device of claim 11,wherein the storage network system is a Serial Attached SCSI (SAS)storage network system.
 13. The routing storage device of claim 11,wherein the reducing the power consumption of the zone comprisesdisabling a physical connection between the routing storage networkdevice and the one of the storage network devices.
 14. The routingstorage device of claim 11, wherein the processor identifies therespective zone as being used if the zone is accessed by another of thestorage network devices in another of the plurality of zones or if thezone does not access another of the storage network devices in anotherof the plurality of zones after the respective zone is identified asbeing unused.
 15. A computer program product for managing a storagenetwork system comprising a plurality of zones, each of the plurality ofzones comprising at least one storage network device, the computerprogram product embodied on a non-transitory computer-readable storagemedium having computer-readable program code portions stored thereon,the computer-readable program code portions comprising: computer programcode for detecting a link-down event associated with one of the storagenetwork devices; wherein the link-down event is at least one of a devicefailure, a cable failure, and a planned device power interruption;computer program code for identifying one of a plurality of zones wherethe link-down event occurred; computer program code for transmitting abroadcast signal in the storage network giving notice of the detectedlink-down event; computer program code for determining whetheralternative storage network devices in the identified one of theplurality of zones where the link-down event occurred are in a link-downstate, wherein at least a zone table and a routing table is used for thedetermining; computer program code for, in response to all of thestorage network devices being in the link-down state, placing theidentified one of the plurality of zones where the link-down eventoccurred in a down state; and computer program code for identifying oneof the plurality of zones as being unused if the zone is not accessed byanother of the storage network devices in another of the plurality ofzones and if the zone does not access another of the storage networkdevices in another of the plurality of zones.
 16. The computer programproduct of claim 15, further comprising computer program code forreducing power consumption of the zone identified as being unused. 17.The computer program product of claim 16, wherein each of the storagenetwork devices is a target storage network device, an initiator storagenetwork device, or a combination thereof.
 18. The computer programproduct of claim 17, wherein the storage network system furthercomprises a routing storage network device configured to communicativelyinterconnect the storage network devices, and wherein the storagenetwork system is a Serial Attached SCSI (SAS) storage network system.19. The computer program product of claim 17, wherein the reducing thepower consumption of the zone comprises disabling a physical connectionbetween the routing storage network device and the one of the storagenetwork devices.
 20. The computer program product of claim 17, furthercomprising computer program code for identifying the respective zone asbeing used if the zone is accessed by another of the storage networkdevices in another of the plurality of zones or if the zone does notaccess another of the storage network devices in another of theplurality of zones after the respective zone is identified as beingunused.